In the past various improvements have been made in the field of refractive vision correction treatments. In many cases these treatments rely upon data obtained in a diagnostic procedure wherein the wavefront aberration and/or topographic data, for example, of the eye are determined.
During the diagnostic examination of an eye, it is desirable for the eye to have a large pupil diameter. Therefore, it is common to use pharmacological pupil dilation to dilate the pupil. However, pharmacological pupil dilation has disadvantages.
Charles E. Campbell describes in the publication “Matrix method to find a new set of Zernike coefficients from an original set when the aperture radius is changed” (J. Opt. Soc. Am. A, February 2003, Vol. 20, No. 2, pages 209 to 217) to form a new set of Zernike coefficients arranged as elements of a vector by multiplying the original set of coefficients, also arranged as elements of a vector, by a conversion matrix formed from powers of the ratio of the new aperture to the original aperture and elements of a matrix that forms the weighting coefficients of the radial Zernike polynomial functions. The conversion matrix according to Campbell is determined corresponding to the extrapolation ratio. As disclosed therein, if the new aperture radius is larger than the original, then the portion of the new surface that lies within the original aperture boundary identically matches the original surface. However, for areas of the new aperture that lie outside the old aperture, the reference states that it is best to normalize by reducing the aperture size of the larger to that of the smaller aperture before making comparisons. Thus there is no disclosure teaching an applicable extrapolation for vision correction treatments.